mirror of https://github.com/koreader/koreader
[i18n] Add Korean keyboard (2-beolsik) (#5053)
limerainne
5 years ago
committed by
Frans de Jonge
parent
8fdb7483a2
commit
53b6e3d018
@ -0,0 +1,440 @@
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-- require('utf8')
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local BaseUtil = require("ffi/util")
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local logger = require("logger")
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--------
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-- # Hangul-input-method Kit for Lua/KOReader
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--------
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-- ## Input method implemented: 2-beolsik (for simplicity, can retrieve many articles for implementation)
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-- ## Classes and their features
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-- * HgSylbls (= Hangul Syllables)
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-- - Determine if a character is in Hangul consonnant, vowel, initial, medial, or final character
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-- - Combine initial, medial[, and final] character into a complete syllables
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-- - Determine if a medial (or final) character can be a double one (can combine another medial (or final) one)
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-- * HgFSM (= Hangul Finite State Machine)
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-- - Process Hangul syllabus combination if the character that user inputs are valid one to be combined
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-- * UIHandler
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-- - To communicate with the actual UI text input box
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--
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-- ## References
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-- https://ehclub.co.kr/2482
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-- :: Hangul syllables combination formula, Hangul unicode composition, FSM reference
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-- https://en.wikipedia.org/wiki/Hangul_consonant_and_vowel_tables
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--------
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----------------------
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-- Hangul Syllables --
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----------------------
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local HgSylbls = {
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-- Hangul character ranges in Unicode
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UNI_HG_BASE = 0xac00,
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UNI_HG_UPPER = 0xd7af,
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UNI_HG_CONSONNANT_BASE = 0x1100,
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UNI_HG_CONSONNANT_UPPER = 0x1112,
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UNI_HG_VOWEL_BASE = 0x1161,
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UNI_HG_VOWEL_UPPER = 0x1175,
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UNI_HG_COMPAT_CONSONNANT_BASE = 0x3131,
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UNI_HG_COMPAT_CONSONNANT_UPPER = 0x314e,
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UNI_HG_COMPAT_VOWEL_BASE = 0x314f,
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UNI_HG_COMPAT_VOWEL_UPPER = 0x3163,
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-- Initial, medial, and final characters to be combined
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CHARS_INITIAL = {"ㄱ", "ㄲ", "ㄴ", "ㄷ", "ㄸ", "ㄹ", "ㅁ", "ㅂ", "ㅃ",
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"ㅅ", "ㅆ", "ㅇ", "ㅈ", "ㅉ", "ㅊ", "ㅋ", "ㅌ", "ㅍ", "ㅎ"},
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CHARS_MEDIAL = {"ㅏ", "ㅐ", "ㅑ", "ㅒ", "ㅓ", "ㅔ", "ㅕ", "ㅖ", "ㅗ", "ㅗㅏ", "ㅗㅐ", "ㅗㅣ", "ㅛ",
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"ㅜ", "ㅜㅓ", "ㅜㅔ", "ㅜㅣ", "ㅠ", "ㅡ", "ㅡㅣ", "ㅣ"},
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CHARS_MEDIAL_COMBINABLE = {"ㅗ", "ㅜ", "ㅡ"},
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CHARS_FINAL = {nil, "ㄱ", "ㄲ", "ㄱㅅ", "ㄴ", "ㄴㅈ", "ㄴㅎ", "ㄷ", "ㄹ", "ㄹㄱ", "ㄹㅁ", "ㄹㅂ", "ㄹㅅ",
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"ㄹㅌ", "ㄹㅍ", "ㄹㅎ",
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"ㅁ", "ㅂ", "ㅂㅅ", "ㅅ", "ㅆ", "ㅇ", "ㅈ", "ㅊ", "ㅋ", "ㅌ", "ㅍ", "ㅎ"},
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CHARS_FINAL_COMBINABLE = {"ㄴ", "ㄹ", "ㅂ"},
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-- For faster search, inverse index tables will be constructed in runtime
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IDX_INITIAL = nil,
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IDX_MEDIAL = nil,
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IDX_MEDIAL_COMBINABLE = nil,
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IDX_FINAL = nil,
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IDX_FINAL_COMBINABLE = nil,
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}
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function HgSylbls:create_inverse_tbl()
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HgSylbls:_create_inverse_tbl_impl("CHARS", "IDX", "INITIAL")
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HgSylbls:_create_inverse_tbl_impl("CHARS", "IDX", "MEDIAL")
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HgSylbls:_create_inverse_tbl_impl("CHARS", "IDX", "MEDIAL_COMBINABLE")
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HgSylbls:_create_inverse_tbl_impl("CHARS", "IDX", "FINAL")
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HgSylbls:_create_inverse_tbl_impl("CHARS", "IDX", "FINAL_COMBINABLE")
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end
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function HgSylbls:_create_inverse_tbl_impl(from_prefix, to_prefix, target_tbl)
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-- ref: https://stackoverflow.com/questions/38282234/returning-the-index-of-a-value-in-a-lua-table
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HgSylbls[to_prefix .. "_" .. target_tbl] = {}
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for k, v in pairs(HgSylbls[from_prefix .. "_" .. target_tbl]) do
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-- NOTE '-1' for making indices start from '0'
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HgSylbls[to_prefix .. "_" .. target_tbl][v] = k - 1
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end
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end
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function HgSylbls:get_combined_char(initial, medial, final)
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-- utf8.char()
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return BaseUtil.unichar(HgSylbls:_get_combined_charcode(initial, medial, final))
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end
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function HgSylbls:_get_combined_charcode(initial, medial, final)
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local len_medial = #HgSylbls.CHARS_MEDIAL
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local len_final = #HgSylbls.CHARS_FINAL
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local combined_code = HgSylbls.UNI_HG_BASE
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+ HgSylbls:_initial_idx(initial) * len_medial * len_final
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+ HgSylbls:_medial_idx(medial) * len_final
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local final_idx = HgSylbls:_final_idx(final)
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if final_idx then
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combined_code = combined_code + final_idx
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end
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return combined_code
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end
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function HgSylbls:_initial_idx(char)
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-- double initial can be typed directly from 2-beolsik kbd, hence no table of two chars
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return HgSylbls.IDX_INITIAL[char]
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end
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function HgSylbls:_medial_idx(char)
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char = HgSylbls:_2elem_tbl_to_str(char)
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return HgSylbls.IDX_MEDIAL[char]
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end
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function HgSylbls:_final_idx(char)
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char = HgSylbls:_2elem_tbl_to_str(char)
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return HgSylbls.IDX_FINAL[char]
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end
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function HgSylbls:in_intial(char)
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-- double initial can be typed directly from 2-beolsik kbd, hence no table of two chars
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return HgSylbls.IDX_INITIAL[char] ~= nil
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end
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function HgSylbls:in_medial(char)
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char = HgSylbls:_2elem_tbl_to_str(char)
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return HgSylbls.IDX_MEDIAL[char] ~= nil
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end
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function HgSylbls:in_final(char)
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char = HgSylbls:_2elem_tbl_to_str(char)
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return HgSylbls.IDX_FINAL[char] ~= nil
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end
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function HgSylbls:is_medial_comb(char)
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return HgSylbls.IDX_MEDIAL_COMBINABLE[char] ~= nil
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end
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function HgSylbls:is_final_comb(char)
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return HgSylbls.IDX_FINAL_COMBINABLE[char] ~= nil
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end
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function HgSylbls:in_consonnant_char(char)
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return HgSylbls:_in_target_char_group(char,
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HgSylbls.UNI_HG_CONSONNANT_BASE, HgSylbls.UNI_HG_CONSONNANT_UPPER,
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HgSylbls.UNI_HG_COMPAT_CONSONNANT_BASE, HgSylbls.UNI_HG_COMPAT_CONSONNANT_UPPER)
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end
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function HgSylbls:in_vowel_char(char)
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return HgSylbls:_in_target_char_group(char,
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HgSylbls.UNI_HG_VOWEL_BASE, HgSylbls.UNI_HG_VOWEL_UPPER,
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HgSylbls.UNI_HG_COMPAT_VOWEL_BASE, HgSylbls.UNI_HG_COMPAT_VOWEL_UPPER)
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end
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function HgSylbls:_in_target_char_group(char, base, upper, compat_base, compat_upper)
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local code = BaseUtil.utf8charcode(char) -- utf8.codepoint()
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if code == nil then
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return false
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end
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local result = base <= code and code <= upper
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local result_compat = false
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if compat_base ~= nil then
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result_compat = compat_base <= code and code <= compat_upper
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end
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return result or result_compat
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end
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function HgSylbls:_2elem_tbl_to_str(str_or_tbl)
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-- if the type of argument is a 'table',
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-- then it is a double medial/final character
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if type(str_or_tbl) == "table" then
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local tbl = str_or_tbl
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return tbl[1] .. tbl[2]
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end
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-- otherwise, return an argument as-is
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return str_or_tbl
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end
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-- initialize HgSylbls inverse index table
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HgSylbls:create_inverse_tbl()
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---------------
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-- UI interface mock; will be implemented
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---------------
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local UIHandler = {}
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function UIHandler:put_char(char)
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logger.dbg("UI:put_char()", char)
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end
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function UIHandler:del_char()
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logger.dbg("UI:del_char()")
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end
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function UIHandler:del_put_char(char)
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UIHandler:del_char()
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UIHandler:put_char(char)
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end
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----------------------
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-- Hangul Automata --
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----------------------
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local HgFSM = {
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STATE = {
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IDLE = 0,
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GOT_INITIAL = 1,
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GOT_MEDIAL = 2,
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GOT_FINAL = 3,
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GOT_DOUBLE_MEDIAL = 4,
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GOT_DOUBLE_FINAL = 5,
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},
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initial = nil,
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medial = nil,
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final = nil,
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fsm_state = nil,
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fsm_prev_states = {},
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do_not_del_in_medial = false,
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ui_handler = nil,
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}
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function HgFSM:init(ui_handler)
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HgFSM:clean_state()
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HgFSM.ui_handler = ui_handler
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end
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function HgFSM:clean_state()
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HgFSM.initial = nil
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HgFSM.medial = nil
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HgFSM.final = nil
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HgFSM.fsm_prev_states = {HgFSM.STATE.IDLE}
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HgFSM.fsm_state = HgFSM.STATE.IDLE
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HgFSM.do_not_del_in_medial = false
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end
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function HgFSM:_push_state(state)
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HgFSM.fsm_prev_states[#HgFSM.fsm_prev_states+1] = state -- append a state
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HgFSM.fsm_state = state
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end
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function HgFSM:_pop_state()
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local prev_state = HgFSM.fsm_prev_states[#HgFSM.fsm_prev_states]
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table.remove(HgFSM.fsm_prev_states) -- pop last item
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HgFSM.fsm_state = HgFSM.fsm_prev_states[#HgFSM.fsm_prev_states]
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return prev_state
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end
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function HgFSM:process_char(char)
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if HgFSM:_should_handle_as_target_char(char) then
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HgFSM:_process_hg_char(char)
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else
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HgFSM:_process_generic_char(char)
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end
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end
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function HgFSM:process_bsp(char)
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if HgFSM.fsm_state == HgFSM.STATE.IDLE or HgFSM.fsm_state == HgFSM.STATE.GOT_INITIAL then
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HgFSM:_process_generic_bsp()
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else
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HgFSM:_process_hg_bsp_except_initial()
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HgFSM:_process_hg_char_update_ui(true) -- true: always remove the current character in edit
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end
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end
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function HgFSM:_should_handle_as_target_char(char)
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if HgSylbls:in_consonnant_char(char) then
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return true
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elseif HgSylbls:in_vowel_char(char) and HgFSM.fsm_state ~= HgFSM.STATE.IDLE then
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return true
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end
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return false
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end
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function HgFSM:_process_generic_char(char)
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HgFSM:clean_state()
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HgFSM.ui_handler:put_char(char)
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end
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function HgFSM:_process_generic_bsp(char)
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HgFSM:clean_state()
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HgFSM.ui_handler:del_char()
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end
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function HgFSM:_process_hg_char(char)
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local result = HgFSM:_process_hg_char_impl(char)
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if result then
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HgFSM:_process_hg_char_update_ui()
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else -- e.g. single vowel character
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HgFSM:_process_generic_char(char)
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end
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end
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function HgFSM:_process_hg_bsp_except_initial()
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local prev_state = HgFSM:_pop_state()
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if prev_state == HgFSM.STATE.GOT_MEDIAL then
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HgFSM.medial = nil
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elseif prev_state == HgFSM.STATE.GOT_DOUBLE_MEDIAL then
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HgFSM.medial = HgFSM.medial[1]
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elseif prev_state == HgFSM.STATE.GOT_FINAL then
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HgFSM.final = nil
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elseif prev_state == HgFSM.STATE.GOT_DOUBLE_FINAL then
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HgFSM.final = HgFSM.final[1]
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end
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end
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function HgFSM:_process_hg_char_impl(char)
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if HgFSM.fsm_state == HgFSM.STATE.IDLE then
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HgFSM:_process_hg_char_new_hg(char)
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elseif HgFSM.fsm_state == HgFSM.STATE.GOT_INITIAL then
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if HgSylbls:in_consonnant_char(char) then
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HgFSM:_process_hg_char_new_hg(char)
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else
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HgFSM:_process_hg_char_push_medial(char)
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end
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elseif HgFSM.fsm_state == HgFSM.STATE.GOT_MEDIAL then
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if HgSylbls:in_vowel_char(char) then
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local dbl_medial_cand = {HgFSM.medial, char}
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if HgSylbls:is_medial_comb(HgFSM.medial) and HgSylbls:in_medial(dbl_medial_cand) then
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HgFSM:_process_hg_char_push_medial(dbl_medial_cand, true)
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else
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return false
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end
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else
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HgFSM:_process_hg_char_push_final(char)
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end
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elseif HgFSM.fsm_state == HgFSM.STATE.GOT_DOUBLE_MEDIAL then
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if HgSylbls:in_vowel_char(char) then
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return false
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else
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HgFSM:_process_hg_char_push_final(char)
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end
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elseif HgFSM.fsm_state == HgFSM.STATE.GOT_FINAL then
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if HgSylbls:in_vowel_char(char) then
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HgFSM:_process_hg_char_borrow_initial_push_next_medial(
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nil, HgFSM.final, char)
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else
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local dbl_final_cand = {HgFSM.final, char}
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if HgSylbls:is_final_comb(HgFSM.final) and HgSylbls:in_final(dbl_final_cand) then
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HgFSM:_process_hg_char_push_final(dbl_final_cand, true)
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else
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HgFSM:_process_hg_char_new_hg(char)
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end
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end
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elseif HgFSM.fsm_state == HgFSM.STATE.GOT_DOUBLE_FINAL then
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if HgSylbls:in_vowel_char(char) then
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HgFSM:_process_hg_char_borrow_initial_push_next_medial(
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HgFSM.final[1], HgFSM.final[2], char)
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else
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HgFSM:_process_hg_char_new_hg(char)
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end
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end
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return true
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end
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function HgFSM:_process_hg_char_new_hg(char)
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HgFSM:clean_state()
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HgFSM:_push_state(HgFSM.STATE.GOT_INITIAL)
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HgFSM.initial = char
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end
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function HgFSM:_process_hg_char_push_medial(char, is_double)
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if is_double then
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HgFSM:_push_state(HgFSM.STATE.GOT_DOUBLE_MEDIAL)
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else
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HgFSM:_push_state(HgFSM.STATE.GOT_MEDIAL)
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end
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HgFSM.medial = char
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end
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function HgFSM:_process_hg_char_push_final(char, is_double)
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if is_double then
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HgFSM:_push_state(HgFSM.STATE.GOT_DOUBLE_FINAL)
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else
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HgFSM:_push_state(HgFSM.STATE.GOT_FINAL)
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end
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HgFSM.final = char
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end
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function HgFSM:_process_hg_char_borrow_initial_push_next_medial(curr_final, next_init, next_medial)
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local next_init_cand = next_init
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HgFSM.final = curr_final
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HgFSM:_pop_state() -- go to previous state
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HgFSM:_process_hg_char_update_ui() -- apply UI the borrow of final character
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HgFSM:_process_hg_char_new_hg(next_init_cand)
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HgFSM:_push_state(HgFSM.STATE.GOT_MEDIAL)
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HgFSM.medial = next_medial
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HgFSM.do_not_del_in_medial = true -- previous character in edit has to be maintained
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end
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function HgFSM:_process_hg_char_update_ui(should_undo_in_initial)
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should_undo_in_initial = should_undo_in_initial or false
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if HgFSM.fsm_state == HgFSM.STATE.GOT_INITIAL then
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if should_undo_in_initial then
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HgFSM.ui_handler:del_char()
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end
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HgFSM.ui_handler:put_char(HgFSM.initial)
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|
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elseif HgFSM.fsm_state == HgFSM.STATE.GOT_MEDIAL or HgFSM.fsm_state == HgFSM.STATE.GOT_DOUBLE_MEDIAL then
|
||||
local combined_char = HgSylbls:get_combined_char(HgFSM.initial, HgFSM.medial, nil)
|
||||
if HgFSM.do_not_del_in_medial then
|
||||
HgFSM.do_not_del_in_medial = false
|
||||
HgFSM.ui_handler:put_char(combined_char)
|
||||
else
|
||||
HgFSM.ui_handler:del_put_char(combined_char)
|
||||
end
|
||||
|
||||
elseif HgFSM.fsm_state == HgFSM.STATE.GOT_FINAL or HgFSM.fsm_state == HgFSM.STATE.GOT_DOUBLE_FINAL then
|
||||
local combined_char = HgSylbls:get_combined_char(HgFSM.initial, HgFSM.medial, HgFSM.final)
|
||||
HgFSM.ui_handler:del_put_char(combined_char)
|
||||
|
||||
end
|
||||
end
|
||||
|
||||
|
||||
return {
|
||||
UIHandler = UIHandler,
|
||||
HgFSM = HgFSM,
|
||||
}
|
||||
Loading…
Reference in New Issue